Air conditioning system



Nov. 7, 1944; L. B. MILLER AIR CONDITIONING SYSTEM Original Filed July 16, 193' STORAGE.

- (BATTERY INVENTOR. Lac '3. Millcn TO HOUSE LlNES Patented Nov. 7,

AIR CONDITIONING SYSTEM Leo B. Miller, Milwaukee, Wis., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn, a-corporation of Delaware Original application July 16, 1937, Serial No. 154,023, new Patent No. 2,284,914, dated June 2, 1942. Divided and this application Novembe! 3, 1941, Serial No. 417,601

Claims. (01. 62-4) This invention relates to pneumatic control systems and its object is to provide a means whereby in a system including an internal combustion engine' the engine provides the source of pneumatic force or pressure utilized by the pneumatic control system.

Thus in pneumatically controlled air conditioning systems or the like wherein an internal combustion engine is utilized, my invention provides an arrangement whereby the pneumatic system is connected to the intake manifold of the internal combustion engine so that the engine will produce a vacuum in the pneumatic system, the vacuum in the pneumatic system providing for operation of the various pressure responsive devices in response to atmospheric pressure.

Another object of my invention is to provide an automatic control system of the pneumatic type wherein the pneumatic system is connected to the intake manifold of an internal-combustion engine forming part of the system.

This application is a division of my previously filed application, Serial No. 154,023, filed July 16, 1937, now Patent No. 2,284,914, issued June 2, 1942.

Referring to the drawing, reference character I indicates a conditioning chamber, this chamber discharging into the inlet of a fan 2 which is connected by a discharge duct 3 to the conditioned space 4. Atits other end the conditioning chamber I is connected to the space 4 by a return duct 5. The conditioning chamber 1 is also provided with a suitable fresh air inlet 6, this duct having the usual damper means (not shown) for controlling the flow of fresh air into the conditioning chamber. In the conditioning chamber I is a cooling coil In for cooling the air before it is passed to the conditioned space. With the arrangement described, it;.will be apparent that a mixture of fresh and return air is passed over the cooling coil In where it is cooled and then passed to the space 4.

The cooling coil III is herein shown as forming part of a compression refrigeration system, this system including also a compressor I I, a condenser I2, and an expansion valve I4, the discharge of the compressor ll being connected to the re-' frigerant inlet of the condenser 12 by a pipe is,

and the refrigerant outlet of the condenser l2 being connected to the expansion valve. M by a pipe I6. The outlet of the cooling coil l0 is-connected by a suction line H to the compressor II. The operation of compression refrigeration sys- However, it may be stated that operation of the compressor causes chilling of the cooling coil Ill and the temperature of the coolingcoil III will vary with the speed of the compressor and also with the temperature of the air being passed in contact with said coil.

Reference character indicates generally an internal combustion engine, this engine having the usual exhaust manifold 2|, intakemamfold 22, generator 23, fly-wheel 24 and starting motor 25. The fly-wheel 24 is connected to a drive shaft. In this manner the engine 2!! drives the compressor II and also drives the fan 2. The drive shaft 26 also drives agenerator 33 by means of pulleys 34 and 35 which cooperate with belts 26. The generator 33 is adapted to supply electricity for domestic use and for this purpose is preferably of the third brush type having a storage battery 31 floating across thegenerator ter- It will be understood. that a suitable cutout may be provided for preventing discharge of the storage battery through the generator when saidgenerator is not running 4 In accordance with my invention, the engine is automatically started and\ stopped inaccordance with the air conditioning load. When the engineis started, it is necessary to disconnect it from its load and for this purpose an automatic clutching'device is provided. The fly-wheei 24 containsa suitable clutching mechanism, this mechanism being actuated by means of a clutch collar 42. The clutch collar 42 is actuated by a bell crank lever 43. which is pivoted at 44, and which has an actuating arm 45 connected to the piston rod 46, which in turn is connected to piston 41 located within cylinder 48. The interior of the cylinder 48 is connected to the intake manifold by means of a conduit 49. A spring 50 is located within the cylinder 48 and is arranged to urge the piston 41 outwardly, this causing movement of the clutch collar 42 for disengaging the clutch. When the engine is running, how ever, a vacuum is developed within the intake manifold 22, this causing evacuation of the cylinder 48, which results in piston 4'! moving to the left against the action of spring 50, thereby caus- -ing engagement of theclutch. The automatic tems of this type is well known in the art, and

therefore no detailed description is'given' here.

clutching mechanism just described therefore acts to disengage the clutch when the engine has spring 55 is connected to the free end of the" switch carrier 53 and urges such carrier against the bellows 52. The bellows 52 contains a suitable volatile fluid wherefore the vapor pressure therein varies with the temperature surrounding the bellows 52. Thus, upon an increase in tem- 'perature,the vapor pressure within the bellows will increase, this causing expansion of the bellows against the action or the spring 55 and tilting the mercury switch towards closed position. Upon a decrease in temperature, however, the vapor pressure within the bellows will decrease, this causing contraction of the bellows .under the action of the spring 55, thereby tilting the mercury switch 54 towards open position. Reference character 55 indicate a storage bat- My invention also contemplates the modulating of the engine speed in accordance with the conditioning load, that is, to increase the engine speed when the conditioning load increases and to decrease the engine speed upon decrease in such conditioning load. For this purpose, a suiterally indicated as 15, this motor being controlled "tery. One terminal ot this battery is grounded 1 as at 51, and the other terminal of said battery is connected to one terminal of mercury switch 54 by means of wires 58 and 58. The other terminal of mercury switch 54 is connected to a wire 68,'and this wire 60 is connected to an ignition coil GI and also to the control terminal of starting relay 52. The starting relay 52 may be of the type shown and described in the Loehr et a1. Patent 1,773,913, dated August 26,1930. This type of starting relay is adaptedto automatically energize the starting motor whenever the .control circuit 01 said relayis energized, and forthis purpose is connected to the battery 55 and to the starting motor 25- by means of wires 63 and 64 respectively. This starting relay is also arranged to prevent energization of the starting motor so long as the engine is in operation, as evidenced by operation of the generator, and for-this purpose is connected to the generator 23 by means of wires, 85 and .66. Reference char- From the description thus far, it should be by means of a pneumatic type of suction pressure controller" 15.

Referring now' to the motor 15, this comprises an armature l8 and a pair of oppositely wound field coils l1 and 18. It will be understood that when field coil 11 is energized, the armature 16 .will be rotated in one direction, and that when the field coil I8 is energized, the armature will 'be rotated in the opposite direction; The armatureli is arranged to drive through a gear train 18, an' operating shaft 88, said operating shaft having attached thereto a lever arm 8| which is ,coqnected by suitable linkage to the throttle valve 18. Thus, rotation of the-armature 18 will cause movement of throttle valve 10.

For controlling the energization of field coils TI and 18, a suitable form of primary control and follow-up mechanism is provided, this comprising a switch arm 82 which is actuated by a bellows 83, and a movable contact carrier 84 formed of insulating material, this contact carrier carrying contacts 85 and 85. The contact carrier 84 is arranged to follow up movements of operating shaft is rotated in the opposite direc- -acter '51 indicatesa suitable generator cut-out tion the carrier '84 will move downwardly. The carrier 84 will therefore assume positions corresponding to the degree of opening of the throttle va ve 18.

The switch arm 82 is arranged to cooperate with contacts 85 and "and for this purpose is pivoted at 88. Thus, upon expansion of the bellows 88, the switch arm 88 will be tilted countera clockwise to bring its contact into engagement with the contact 88. This will cause energizaq tion of the field coil 11 by a circuit as follows:

storage battery 58, wire 58, wire 58, wire 8i, switch apparent that whenever the space temperature rm 82, contact 88, wire 82', field coil ll, wire 88,

is below a predetermined value, the mercury switch 54 will be open, thereby deenergizing the armature I8 and wire 84 to ground. This will' starting relay 82- and the ignition coil 8|, this direction to open the throttle valve, this causing causing the engine to be stopped at which time starting relay, and also the resulting vacuum in the intak manifold causes operation of the automatic clutching mechanism for engaging the clutch, thereby causing-the engine to drive the V compressor, the fan, the generator, and any other en, however,

downward movement of the carrier 84, thereby the automatic clutching mechanism will cause 60 i nga ing the contact 88 from the switch arm disengagement of the*clutch.-

\the space temperature rises abovethe value for i which the'controller .5] is set, the m cury switch 154 will close, thus energizing the ignition circuit 82, thusdeenergizing the motor. Conversely, upon contraction of the bellows 88, the switch arm 82 will be tilted clockwise, thereby bringing it into engagement with the contact 85, this causing energization of the field coil 18 for driving the operating shaft 88 in a direction to close the throttle valve, this simultaneously causing upward movement of the contact carrier 84 which disengages the contact 85 from the switch arm 82. From the foregoing, it will be apparent that the electric motor driving mechanism will cause the throttle valve to assume positions corresponding to the degree of expansion of the bellows. In other words, as the bellows 88 expands, the

apparatus that may be connected to shaft 26. F5 throttle valve 18 will be moved towards open tion.

throttle valve will be moved towards closed posi- For controlling the degree of expansion of the bellows 83 and hence the position of the throttle valve III, the suction pressure controller I8 is provided. Controller I8 comprises a bellows 95, this bellows being fixedly secured at its lower end and cooperating with the actuating arm 98 of a bell crank lever which is pivoted at 91. The bell crank lever also includes a control arm 99 which forms a valve member cooperating with a port 99 for forming a control valve. The bel? lows 95 is connected by means of a conduit I to the suction line H of the refrigeration system. Upon an increase in pressure within th system, the bellows 95 will expand, this causing clockwise rotation of the actuating arm 96 against the 'action of a spring IIII, this moving the valve member 98- away from the port 99. Upon a decrease in suction pressure the bellows will contract under the action of the spring, thereby causing movement of the valve member towards the port 99.

For actuating the bellows 83 of motor I in accordance with changes in suction pressure afiecting controller I8, I utilize the vacuum developed in the intake manifold of the engine 20. For this purpose I provide a receiver I05, this receiver being c mnected to the intake manifold of the engine '1; means of a conduit I08, this conduit having interposed therein a pressure regulating valve I01 and a check valve I08 which is arranged to open towards the intake manifold. The pressure rraulating valve I01 is of known form and is arranged to close when the pressure in receiver I05 is reduced to a predetermined value. By this arrangement, a constant subatmospheric pressure is maintained within the receiver I05 even though the subatmospherie pressure within the intake manifold may vary. Also connected to the receiver I05 is a conduit I09 which leads to the bellows 83. This conduit is also connected-t0 the port 99 of the pressure controller I6 by means of conduit IIO. Interposed in the conduit I09 is a restriotor III. This restrictor is shown as taking the form of a needle valve and this 'valve is adjusted to havea capacity less than the capacity of the port 99.

When the suction pressure of the refrigeration system fails to a predetermined value, the valve member 99 will be caused to engage the port 99. This will prevent admittance of air into conduit IIII through port 99 thereby causing the pressure within conduits I09 and H0, and within the bellows 83 to decrease to a value equal to the subatmospheric pressure maintained within the receiver I05. This will cause the bellows 83 to contract to a maximum extent, thereby rotating the switch arm 82 around its pivot 89 in a clockwise direction, thus compressing spring 90 and causing engagement of switch-arm 82 with contact 98. This, in the manner previously described, will cause the motor to rotate until the contact carrier 84 is at its uppermost limit, at which time the throttle valve 10 will bemoved to the minimumfuel feeding position.- As the suction pressure begins to rise, the bellows 95 will expand causing movement of the valve member 98 away from port 99. This will admit air into the conduits I I0 and I09 and into the bellows 83, thereby causing a rise in pressure therein, this rise in pressure permitting expansion of thebellows 83 under the action of the compression spring 99,

wise direction to bring it into engagement with the contact 98, which will cause operation of the motor in a direction to open the valve, the valve therebybeingopened to such an extent that contact carrier 84 is moved downwardly a sufllcient distance to disengage switch arm 82 from contact 86. Upon a further increase in suction pressure, the valve member 98 of controller I8 will be shifted farther from port 99, thereby admitting more air into the conduits I09, I I0 and the bello'ws 83, thus causing expansion of the bellows 83 farther, which in turn results. in the throttle valve I0 being moved further towards open position. When the suction pressure rises to a predetermined maximum the valve member 98 will be moved to a position wherein it leaves port 99 unobstructed, this causing a maximum flow of air through such port, thus causing bellows 83 to be expanded to a maximum, which will in turn result in the throttle valve 10 being moved to a wide open position. From the foregoing, it will be apparent that with the controlarrangement just described, the throttle valve will be graduatingly controlled in accordance with the suction pressure of the refrigeration system, the throttle valve being O ened to increase the engine speed, when the suction pressure increases, and being closed for decreasing the engine speed when the suction pressure decreases.

From the foregoing, the operation of the system in its entirety is readily apparent. Summarizing the operation, whenever the engine 29 is started in response to the controller 5|, the refrigeration system will of course be put in operation so as to reduce the pressure in the evapoport 99 so as to obstruct the admission of air into pipe IIO. Thus as described above, the controller 19 will control the pressure in the pipe H8 and in the bellows 83 depending upon the suction pressure, and the throttle valve I0 will be positioned accordingly, that is, in accordance with the suction pressure. In other words, the engine 20 will be controlled in response to the suction pressure so that the power developed by the engine will be proportionate to the load on the coil I0.

By connecting the receiver of the pneumatic system to the intake manifold of the engine, the

pneumatic system is operated under vacuum so that atmospheric air bleeds into the system. This, as distinguished from more conventional systems wherein there is. a source of compressedair which is supplied to the pneumatic system,

and air pressure is bled ofi from the pneumatic system. With the arrangement I have provided, the necessity of a source of compressed air for the pneumatic system is entirely obviated, it being only necessary to connect the receiver of the pneumatic system to the intake manifold of the engine through the pressure regulating valve I91.

The form of my invention which I have disclosed is representative and many variations and modifications will occur to those skilled in the art. The scope of'my invention is therefore to be determined only in accordance with the claims appended hereto.

I claim as my invention;

J air into heat exchange relationship with said device for a conditioning action, means .for causing a flow of heat exchange medium. through said device comprising'a compressor, an internal com-- bus'tion engine for driving said compressor, said engine having an intake .manifold, a variable speed controller for said internal combustion en- 'gine, a fluid actuateddevice for causing movement of. said variable speed controller, means for combustion engine for driving said compressor,

supplying actuating fluid to .said fluid actuated device, said last mentioned means including a fluid flow controlling device responsive to a load conditionon the system for controlling the sup- ,controllen including a control valve responsive to a condition indicative of the demand for compressor operation, and means whereby said internal combustion engine maintains a pressure within said pneumatic system other than atmospheric pressure.

3. In an air conditioning system, a conditioning chamber through which airto beconditioned is passed, an evaporator coil in heat transfer relationship with said'chamber, a compressor for supplying refrigerant to said coil, an internal a speed controller tor varying'the speed of said engine, a pneumatic control system for said speed controller including a control valve responsive to a condition indicative of the demand for compressor operation, and a connection between the conduit or said .pneumatic control system and the intake manifold of said engine tending to maintain a vacuum within said conduit. I

4. A system of the character described comprising in combination, an internal combustion engine, a throttle valve in the fuel supp y thereto for varying the speed of said engine, a pneumatic system, means operated by said engine for developing a pressure other than atmospheric within said pneumatic system, valve means connecting said pneumatic system to the atmosphere, means operating said valve means to maintain a pressure within said pneumatic system which is dependent upon the demand for engine operation, and means positioning said throttle valve in accordance with said pressure. v

' 5. A refrigeration system comprising in combination, an internal combustion engine, a re-.

frigerant compressor driven thereby, a throttle valve in the fuel supply to said engine for varying the speed thereof, a pneumatic system. means operated by said engine for developing a pressure other than atmospheric in said pneumatic system, valve means connecting said pneumatic system, to the atmosphere, means operating said valve means in response to the pressure on the suction side of said compressor for varying the pressure in said pneumatic system in accordance with said suctionpressure, and means operating said throttle valve and hence varying the speed of the engine in accordance with the pressure in said pneumatic system. 7

@LEO n. MILLER. 

